Saturday, July 2, 2016

Scientists Find New Kind of Fukushima Fallout

A Tokyo Electric Power Co. (TEPCO) employee, wearing a protective suit and a
mask, walks in front of the No. 1 reactor building at TEPCO's Fukushima Daiichi
nuclear power plant. (photo: Toru Hanai/Bloomberg)

Scientists
Find New Kind of Fukushima Fallout

By Sam Lemonick, Forbes

01 July 16

Some
of the radioactive material that escaped the Fukushima Daiichi nuclear reactor
in 2011 took a form no one was looking for, scientists have discovered. Now
they have to figure out what it means for Japan and for future disasters.

Radioactive
cesium—specifically, cesium-137—is one of the waste products of nuclear power.
It’s also one of the most dangerous substances in a nuclear disaster like
Chernobyl or Fukushima.

One
reason why is that the type of radiation it emits is particularly damaging to
our bodies. Another is that cesium-137 dissolves in water. That means it can
spread quickly through the environment and get into the plants, animal and
water we consume.

Until
now, scientists and disaster experts thought cesium-137 fallout from the
Fukushima reactor meltdown was in this soluble form. That guided their cleanup
efforts, like removing and washing topsoil, and helped them map where radiation
might spread.

It
turns out that wasn’t entirely true. Satoshi Utsunomiya, a geochemist at Kyushu
University in Japan, announced over the weekend that he had found cesium-137 in
a new form: trapped inside tiny glass particles that spewed from the damaged
reactors. These particles are not water soluble, meaning we know very little
about how they behave in the environment—or in our bodies. He found the
particles in air filters placed around Tokyo at the time of the disaster.

According
to Utsunomiya, high temperatures inside the malfunctioning reactors at the
Fukushima plant melted and broke down the concrete and metal in the buildings.
Silica, zinc, iron, oxygen and cesium-137 fused into millimeter-wide glass
microparticles, each about the size of a pin’s head. Lifted into the atmosphere
by the fires raging at the plant, they then blew about 240 kilometers southeast
to Tokyo.

“As
much as 89% of all of the cesium [in Tokyo] was in fact in these particles.
It’s profound,” says Daniel Kaplan, a geochemist at Savannah River National
Laboratory in South Carolina. He attended Utsunomiya’s lecture describing the
findings at the ongoing Goldschmidt Conference in
Yokohama, Japan.

Kaplan
says similar particles were observed near the Chernobyl reactors after the
explosion there in 1986. But they were only seen within about 30 kilometers;
beyond that, cesium-137 was only observed in rain.

The
discovery could change how we model fallout from nuclear disasters. Kaplan
explains that it might add a new variable to the models we use to predict where
radioactive particles will go and how long they’ll stay there. It might also
change how we treat cesium-137 during cleanup and monitoring.

It is
probably still too early to say what this means for people living in Tokyo or
elsewhere in Japan. Kaplan thinks the amount of radiation they received
probably hasn’t changed. Whether they got it from water-soluble cesium-137 or
from these particles, the radiation dose was the same—and for Tokyo residents,
that number was within the margin of safe exposure.

The
bad thing about water-soluble cesium-137 is that it can easily get into our
bodies from soil by way of plants and animals. This new discovery alleviates
that concern. But it opens up a new possibility we know little about.

“If
the particles are in the air—because that’s how they get to Tokyo—then when you
are aspirating this air you should find them in some ways on your lungs,” says
Bernd Grambow, who studies nuclear waste chemistry as head of the SUBATECH
laboratory in France.

Water-soluble
cesium-137 that makes it into our lungs passes into the bloodstream and is peed
out within a few weeks. But Grambow says we really don’t know what happens to
insoluble cesium-137-containing particles if they get in our lungs. Some of
them are likely coughed out or removed by our lungs’ other normal processes. As
for the rest, Grambow says we don’t know how long they might remain.

He
cautions that any internal radiation from particles containing cesium-137 would
be much less than the doses people got from external radiation, which would
come from cesium-137 and other radioactive elements in the soil or the
environment around them. “We don’t know very much, and my point is only that
they should be studied,” Grambow says.

Utsunomiya’s
next step is finding out how much of the cesium-137 that ended up in soils in
Tokyo and elsewhere was in these glass particles. That way, researchers will be
able to better understand how cesium made its way out of the reactor and into
the environment.

"The master class
has always declared the wars; the subject class has always fought the battles.
The master class has had all to gain and nothing to lose, while the subject
class has had nothing to gain and everything to lose--especially their
lives." Eugene Victor Debs